Final answer:
The Specificity principle states that our bodies will adapt specifically to the type of training we perform, whether it's aerobic or anaerobic. The principle that states our bodies will physiologically adapt according to whether we are training aerobically or anaerobically is the Specificity principle.
Step-by-step explanation:
The principle that states our bodies will physiologically adapt according to whether we are training aerobically or anaerobically is the Specificity principle. This principle posits that to become better at a particular exercise or skill, you must perform that exercise or skill. For example, a runner would train by running to improve racing endurance, while a weightlifter would train by lifting weights to increase muscle strength. The Specificity principle is a cornerstone in designing effective fitness programs.